A significant reduction in cost can be achieved by substituting a metal part with a molded article of a reinforced resin material. Accordingly, active studies on substitution have been performed (see, for example, Patent Literature 1 and Patent Literature 2).
The resin material to be used as described above has advantages such as (1) a reduction in weight, (2) an improvement in electrical insulation, and (3) an improvement in chemical resistance. Accordingly, applications of the resin material have expanded into substitute materials for various metal parts, and its amount of use has been increasing. In addition, particularly in the field of medical materials, a metal material such as titanium has been used as a material for implantation such as an artificial bone, an artificial joint, or an artificial tooth root. In recent years, however, the resin material has been utilized also in such field.
However, as compared to a metal, the resin material generally has problems such as having a large linear coefficient of expansion, having a low heat-resistant temperature and mechanical strength, being liable to deform or decompose, being liable to dissolve in an organic solvent, and being liable to expand by water absorption. Therefore, it is not easy to substitute a metal part with a resin part.
To solve the above-mentioned problems, there have been proposed synthetic resin products having various functions enhanced in accordance with intended applications by selecting a resin having high heat resistance such as an engineering plastic or a super engineering plastic. Further, there is also a proposal of a composite material having inorganic particles blended therein as a filler.